BEIJING, Dec 26 (Reuters) - Chinese imports of coal from key supplier Australia slipped in November from a year ago, customs data showed, hit by heavy traffic congestion in Australian ports.

Shipments from Australia COA-AUCN-IMP fell 0.3 percent in November from the same month a year ago to 5.59 million tonnes, data from the General Administration of Customs showed on Tuesday. That compared with October’s 5.61 million tonnes.

More than 300 large dry cargo ships have been waiting outside Chinese and Australian ports in a maritime traffic jam for over a month, choking supplies to the world’s second-largest economy.

“Demand for high-quality coal is surging as the country has imposed stringent rules to curb emissions and improve energy efficiency,” said Wang Fei, a coal analyst at Huaan Futures.

High-grade coal from Australia, with lower pollutants such as sulphides and higher energy value, has seen increasing demand from utilities and industrial plants in China.

As part of a national battle against air pollution, China aims to reduce consumption of low-grade bulk coal by 200 million tonnes by 2020.

China is expected to import around 260 million tonnes of coal in 2017, according to data from China National Coal Association.

Over the first 11 months, the world’s largest coal consumer brought in 248.17 million tonnes of the commodity..

Arrivals from Russia COA-RUCN-IMP rose 10.9 percent from a year earlier to 1.92 million tonnes in November, customs data showed. Imports from Mongolia COA-MNCN-IMP were down 17.8 percent at 2.76 million tonnes.

Indonesian coal supplies COA-IDCN-IMP tumbled 33.9 percent from a year ago to 3.41 million tonnes, dampened by the decreasing demand for lower-grade varieties of the fuel.

China’s appetite for coal was buoyed earlier this month when the central government scaled back its plan to convert northern cities to using natural gas for heating due to a shortage of that commodity.

Thermal coal on the Zhengzhou Commodity Exchange soared on Dec. 18 to a record 645.4 yuan ($98.55) a tonne.

State planner, the National Development and Reform Commission (NDRC), has approved three new coal mines with combined annual capacity of 32 million tonnes since the beginning of December, a bid to ensure coal supplies during future winters.

The NDRC has also urged coal miners to put more high-grade coal projects into operation “as soon as possible”.

Local media reported on Thursday last week that China has loosened restriction on coal imports through Shanghai and several other ports.